Valve and method of making the same

ABSTRACT

A double seat valve having a valve body formed of conductive metal with a relatively thin-wall top portion forming the side wall of an open ended cavity, and a bottom portion having a chamber therein communicating with the cavity. The bottom portion has first and second axially displaced ports communicating with the chamber, and a first valve seat in the chamber between the first and second ports. A valve top member has a portion extending into the cavity, that portion having a bottom enc closing the chamber, and an upwardly and inwardly tapered surface facing the wall. The wall is defomed into tight engagement with the tapered surface by forces created by a transient magnetic field of high intensity. The top member has an axial passage therethrough communicating with the chamber through the bottom end which has a second valve seat formed therein, and a third port communicating with the passage. A valve member is positioned between the first and second seats and is secured to a valve stem which extends through the passage, and which actuates the valve member between a first position in which it engages the first seat thereby blocking flow between the first and second ports and permitting flow between the second and third ports, and a second position in which it engages the second seat thereby blocking flow between the second and third ports and permitting flow between the first and second ports.

United States Patent 1191 Beck [ 1 Dec. 11, 1973 VALVE AND METHOD OFMAKING THE 57 ABSTRACT SAME A double seat valve having a valve bodyformed of [75] Inventor: Maurice E. Beck, Fort Wayne, Ind. conductivemetal with a relatively thin-wall top portion forming the side wall ofan open ended cavity, [73] Asslgnee' gr valve Fort Wayne and a bottomportion having a chamber therein communicating with the cavity. Thebottom portion has Filedi 1971 first and second axially displaced portscommunicating with the chamber, and a first valve seat in the cham- [211Appl' 18703l ber between the first and second ports. A valve top memberhas a portion extending into the cavity, that Cl 137/6255, /3 portionhaving a bottom enc closing the chamber, and 9/42] M an upwardly andinwardly tapered surface facing the [51] Int. Cl. Fl6k 11/00 wall, Thewall is defomed into tight engagement with [58] Field of Search137/625.5; the tapered surface by forces created by a transient 29/157.lR, 421 M; 285/3324, 334.5, 382; magnetic field of high intensity. Thetop member has 251/367, 366 an axial passage therethrough communicatingwith the chamber through the bottom end which has a second [56]References Cited valve seat formed therein, and a third port communi-UNITED STATES PATENTS eating with the passage. A valve member ispositioned 3 593 745 7/1971 Myers 137 6255 x between first and Seats andis Secured to 3:662:761 5 1972 Hoffman 29 1571 R valve Stem whichextends through the Passage, and 2,976,907 3/1961 Harvey et al 29/421 Mwhich actuates the valve member between a first P 3,196,529 7/1965Schwinghamer 29/421 M tion in which it engages the first seat therebyblocking 3,214,511 10/1965 Franklin 29/421 M flow between the first andsecond ports and permitting 3,602,531 8/1971 Patry t 285/328 X flowbetween the second and third ports, and a second J 6 :2 position inwhich it engages the second seat thereby aun 3,578,286 5 1971 Klimek29/1571 R 3:235 ag:tiff;: f i gg gg gggs g 2,892,608 6/1959 Collins...251/367 x i2; 75.. 5- 1 3,333,327 8 1967 L 29 421 M men I 12 Claims, 12Drawing Figures Primary Examiner-Samuel Scott Attorney-Harold B. Hood etal.

I4 11a 74 H6 64 927 90 1'5 no I se ' 7 L mi 66 1 B6 q 8B 70 QZ\ Z: 1515;. as I04 l ee Pmmmntc 1 1 ms 3.777.783

' SHEET 2 OF 5 INVENTOR MAURICE E.BECK 12mm, $613M ATTORNEYS PATENTEDUEC1 1 ma 3.777383 I so EEEEEEEEEEE CK PAIENIEIIIIEI: I I I975 SHEET 5 {IF5 INVENTOR. MAURICE E.BECK M, M M.

ATTORNEYS VALVE AND METHOD OF MAKING THE SAME BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates generally tovalve assemblies and methods of making the same, and more particularlyto a double seat valve assembly and methodof making the same.

2. Description of the Prior Art Double seat valves which are commonlyused in refrigeration systems comprise three ports with a valve memberselectively actuable between a first position in which flow is blockedbetween a first and second port and permitted between the second andthird port, and a second position in which flow is blocked between thesecond and third port and permitted between the first and second port.One form of double seat valve and a method of making the same isdisclosed in U.S. Pat. No. 2,536,727. In that valve assembly, first andsecond nipples having passages therein forming first and second portsare attached to the valve body by brazing, and a third nipple having apassage therein forming the third port is attached to the valve body bysilver soldering.

In another known form of double seat valve, the first, second and thirdnipples are integrally formed on the valve body, two of the nippleshaving passages therein directly communicating with the valve chamber. Avalve top member having a passage therein which communicates with thepassage in the third nipple is attached to the valve body by silversoldering.

The attachment of one valve part to another by a silver soldering, whichinvolves heating the area to be soldered to an elevated temperature, maycause distortion and adversely affect the previously assembled packings.In the case of aluminum and brass valves, the flux used in silversoldering may adversely affect the enclosed areas of the valve. Further,silver soldering is a manual operation requiring some dexterity.

In the case of the second known form of double seat valve referred toabove, problems are presented in aligning the passage in the thirdnipple with the passage in the valve top member. Further, the silversolder employed in securing the top member to the valve body tends toblock those passages thus requiring that they be drilled-out, which mayresult in the presence of shavings in the interior of the valve.

Valve parts have been held in an assembled relation by threadedconnections however, such threaded connections tend to leak after aperiod of time which is particularly undersirable in the case of a valveemployed in a refrigeration system where maintenancefree operation for anumber of years is desired.

It is therefore desirable to provide a valve assembly and method ofmaking the same in which the valve parts are held in assembled relationwithout a threaded connection of the necessity for heating the parts asin soldering or brazing.

Apparatus and methods have been developed for forming metals byapplication of transient magnetic fields of high intensity, and suchapparatus and methods have been employed for attaching one part toanother. Such an electromagnetic metal forming apparatus and method asdisclosed in U.S. Pat. Nos. 2,976,907 and 3,429,l59. In accordance withthat apparatus and method, a momentary electrical current pulse of highamperage is applied to a conductive coil thereby producing a transientmagnetic field of high intensity. A

conductive work piece positioned in the field has eddy currents inducedtherein in response to the expanding field, the induced current pulse inthe work piece interacting with the magnetic field to produce a forceacting on the work piece. When the peak value of the current pulse ishigh, for example in the range from 100,000 to l,000,000 amperes, suchas that provided by discharge of a capacitor bank, deformation of thework piece is obtained, the shape of the deformation being dependentupon the configuration of the magnetic field and the position of thework piece relative thereto.

SUMMARY OF THE INVENTION In accordance with the invention, valve partsare secured in assembled relation by deformation of one part caused byforces created by a transient magnetic field of high intensity.

In its broader aspects, the invention provides a valve assemblycomprising a first part formed of conductive metal and having arelatively thin-wall portion forming the side wall of an open endedcavity. A second part is provided having a portion extending into thecavity, the second part portion having means thereon facing the wall forholding the first and second parts in assembled relation. The wall isdeformed into tight engagement with the holding means by forces createdby a transient magnetic field of high intensity.

It is accordingly an object of the invention to provide an improvedvalve assembly.

Another object of the invention is to provide an improved double seatvalve assembly.

A further object of the invention is to provide an improved method ofmaking a valve assembly.

The above-mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will be best understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side cross-sectional viewshowing the improved double seat valve assembly of the invention.

FIG. 2 is a side view of the valve of FIG. 1 as viewed generally alongthe line 22 thereof;

FIG. 3 is a bottom view of the valve of FIG. I as viewed generally alongthe line 3-3 thereof;

FIG. 4 is a side cross-sectional view of the body of the valve of FIG. 1prior to assembly;

FIG. 5 is a front view of the top member of the valve of FIG. 1 prior toassembly;

FIG. 6 is a cross-sectional view taken generally along the line 6-6 ofFIG. 5;

FIG. 7 is a cross-sectional view taken generally along the line 7-7 ofFIG. 1;

FIG. 8 is a side elevational view, partly in cross section, illustratingthe improved method of assembly of the valve of FIG. 1;

FIG. 9 is a cross-sectional view taken generally along the line 99 ofFIG. 8;

FIG. 10 is a cross-sectional view of the electromagnetic metal deformingapparatus employed taken generally along the line 1010 of FIG. 9;

FIG. 11 is a side cross-sectional view showing a safety valve assembledin accordance with the method of the invention; and

FIG. 12 is a side cross-sectional view showing a relief valve assembledby the method of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1through 7 of the drawings, the improved double seat valve of theinvention, generally indicated at 14, comprises valve body 16 formed ofconductive metal, such as aluminum, valve top 18, also formed of metal,such as aluminum, valve member 20 actuated by valve stem 22, and cap 24.

Valve body 16 has an annular, relatively thin-walled top portion 26extending downwardly from its upper end 28 and defining cavity 30 (FIG.4). Bottom portion 27 of valve body 16 has a valve chamber formedtherein comprising upper and lower chamber sections 32, 34 with firstvalve seat 36 therebetween, upper chamber section 32 communicating withcavity 30. Longitudinal axis 38 of valve body 16 extends through cavity30 and chamber sections 32, 34. First port 40 communicates with upperchamber section 32 and with passage 42 in nipple 44 having externalthreads 46 thereon. Second port 48 communicates with lower chambersection 34 and with passage 50 in nipple 52 having external threads 54thereon. Another externally threaded nipple 56 (FIGS. 2, 3) has passage58 therein also communicating with lower chamber section 34. Externallythreaded stud 60 is integrally formed on bottom end 62 of body 16 andmay be employed for mounting valve assembly 14.

Valve top member 18 comprises upper portion 64 and lower portions 66 andhas internally threaded, axial passage 68 formed therein. Passage 68extends between second valve seat 70 formed in bottom end 72 andenlarged passage 74 extending downwardly from upper end 76.

Lower portion 66 of valve top member 18 extends into cavity 30 in valvebody 16 with its bottom end 72 seated against shoulder 78. Lower portion66 of valve top member 18 has surface 80 thereon which tapers upwardlyand inwardly toward axis 38 and which also has axially extending grooves82 formed therein (FIGS. 6 and 7) defining splines 84 therebetween.Annular groove 86 is formed in lower portion 66 of top member 18 betweentapered surface 80 and bottom end 72 and has O-ring 88 seated therein.

As hereinafter more fully described, wall 26 of valve body 16 isdeformed for forces created by a transient magnetic field of highintensity into tight engagement with splines 84 and grooves 82, as bestseen in FIG. 7, thereby compressing O-ring 88 and holding valve body 16and valve top member 18 in assembled relation. It will be seen thatdeformation of wall 26 into engagement with grooves 82 and splines 84 oflower portion 66 of top member 18 inhibits rotation of top member 18with respect to valve body 16.

Nipple 90 having external threads 92 thereon is formed on upper portion64 of valve top member 18 and has passage 94 therein communicating withpassage 68 thereby forming a third port. Valve stem 22 has valvemounting portion 98 integrally joined to its lower end 100 by taperedportion 102. Valve disc 104 formed of suitable material, such as nylon,has portion 106 seated in a recess in valve mounting member 98 andsecured thereto by suitable adhesive. Valve disc 104 has tapered surface108 adapted sealingly to engage valve seat 36. As best seen in FIG. 1,valve mounting member 98, tapered portion 102 of valve stem 22, andvalve disc 104 are positioned in upper chamber section 32 of valve block16.

Valve stem 22 has threaded portion 110 thereon intermediate its ends100, 1 12 which threadedly engages internally threaded passage 68thereby permitting actuation of valve 20 between an upper position, asshown, with tapered portion 102 engaging valve seat 70, and a lowerposition in which tapered portion 108 of valve disc 104 engages valveseat 36. It will readily be seen that in the upper position of valve 20shown in FIG. 1, fluid flow between ports 40 and 94 is blocked whereasfluid flow between ports 40 and 48 is permitted. It will further be seenthat with valve 20 in its lower position sealingly engaging valve seat36, fluid flow between ports 40 and 48 is blocked whereas fluid flowbetween ports 40 and 94 is permitted.

Upper end 112 of valve stem 22 extends upwardly above upper end 76 ofvalve top member 18, and valve stem 22 is adapted to be manually rotatedthereby to actuate valve 20 between its upper and lower positions by hexportion 114 adjacent upper end 112. Leakage of fluid along valve stem 22is prevented by washer 116 and packing 118 in enlarged passage portion74, washer 116 and packing 118 being compressed and retained by nut 120,as shown. Closure cap member 24 threadedly engages upper end 76 of valvetop member 18 thus enclosing upper end 112 of valve stem 22 andproviding additional sealing.

In the embodiment illustrated in FIG. 1, passage 94 is preferablyinclined inwardly and downwardly by a small angle 122, such as 3, sothat its opening 124 into passage 68 will be below threaded portion 110of valve stem 22 when in its upper position.

The double seat valve assembly 14 is particularly adapted for use in arefrigeration system, and when used in such a system, the normal flow ofrefrigerant is from passage 50 and port 48 to port 40 and passage 42. Apressure gauge is coupled to nipple 90, and nipple 56 is adapted for usein charging the system, passage 58 having a check valve (not shown)therein.

Referring now to FIGS. 8, 9 and 10, valve top member 18, with valve stem22 and valve 20 assembled thereon, may be assembled on valve body 16using magnetic forming apparatus 126 of the general type shown in US.Pat. No. 3,429,159. Apparatus 126 has a central opening 128 thereinhaving a diameter greater than the maximum transverse dimension ofnipple and valve top member 18 thereby permitting the assembled valvebody 16 and valve top member 18 to be inserted in and removed fromapparatus 126.

Apparatus 126 comprises a pair of pancake coils 130, 132 respectivelyembedded in members 134, 136 formed of suitable insulating material.Insulating members 134, 136 respectively abut guide members 138, metalplates 140, 142 respectively abut the outer surfaces of members 134,136, and members 134, 136, 138 and plates 140, 142 are held in assembledrelation by suitable clamps 144.

Field shaping plates 146 formed of conductive metal, such as copper, areslideably mounted on guide members 138 for lateral movement between aninner position, as shown in solid lines of FIGS. 8 and 9, and an outerposition as shown in dashed lines at 146a. Field shaping plates 146 havearcuate apertures 148 formed therein which respectively engage wall 26of valve body 16 when field shaping members 146 are in their innerpositions, as shown. Field shaping members 146 are slightly spaced apartin their inner positions to form an air gap by a narrow strip ofinsulation 150 attached to one of the members 146.

It will be seen that when field shaping members 146 are moved laterallyto their outer positions 146a, their apertures 148 are respectivelywithdrawn from opening 128, as shown at dashed lines at 148a, thuspermitting valve assembly 14 to be inserted in opening 128 andsubsequently removed therefrom following the deforming operation.

Coils 130, 132 are preferably connected in series, but may be connectedin parallel. Coils 130, 132 are coupled to a suitable pulse source 152preferably comprising a capacitor bank and a firing circuit, such asthat shown in US. Pat. No. 3,247,440, whereby the charge stored in thecapacitor bank is discharged through coils 130, 132.

In accordance with the method of the invention, lower portion 66 ofvalve top member 18 having valve stem 22 and valve assembled thereon isseated in cavity in valve body 16, as abovedescribed. With field shapingplates 146 withdrawn to their positions 146a, valve assembly 14 is theninserted in opening 128 in magnetic forming apparatus 126, and fieldshaping plates 146 are then moved inwardly to their inner positions withthe edges of apertures 148 engaging wall 26 of valve body 16, as shownin FIGS. 8 and 9. Pulse source 152 is then actuated, as by dischargingits capacitor bank, thereby applying a momentary pulse of high amperageto low resistance coils 130, 132. Application of the high amperage surgeof current to coils 130, 132 generates a rapidly expanding magneticfield of high intensity which, in turn, induces a transient current ofhigh intensity in field shaping plates 146 which is concentrated on theinner edges around apertures 148, thus creating an intense magneticfield in wall 26 of valve body 16. The induced current pulse interactswith this magnetic field to produce a compressive force acting on wall26 which thus deforms it into tight engagement with grooves 82 andsplines 84 on lower portion 66 of valve top member 18, as seen in FIG.7. Following application of the transient magnetic field of highintensity and resultant deformation of wall 26 of valve body 16 intoengagement with lower portion 66 of valve top member 18, field shapingplates 146 are withdrawn to their positions 146a, and the assembledvalve 14 is removed from apparatus 126 through opening 128.

The magnetic deformation method above may be employed in the assembly ofother types of valves. Referring now to FIG. 11, a safety valve is shownhaving valve body 152 formed of suitable metal, such as brass ofaluminum, and thin-walled cap member 154 formed of suitable conductivemetal, such as brass or aluminum. Valve body 152 has a central aperture156 formed therein extending between its lower, threaded end 158 and itsupper end 160. Valve seat 162 is formed in upper end 160 and is normallyengaged by valve member 164 biased to its closed position by spring 166.Annular groove 168 is formed in valve body 152 adjacent its upper end160 and portion 170 of side wall 172 of thin-walled cap member 154adjacent its lower end 174 is deformed into groove 168 by the forcescreated by a transient magnetic field of high intensity, asabove-described.

Referring now to FIG. 12, a portion of a pressure relief valve is shownhaving body 176 formed of suitable metal, such as brass or aluminum, andthin-walled cap member 178 formed of suitable conductive metal, such asbrass or aluminum. Valve body 176 has V-shaped groove 180 formedtherein, and bottom end 182 of side wall 184 of cap member 178 isdeformed into groove 180 thereby engaging tapered surface 186 thereof bymagnetic deformation, as above-described.

It will now be seen that in accordance with the invention, a valveassembly is provided wherein valve parts are held in assembled relationwithout brazed, soldered or threaded connections.

While there have been described above the principles of'this inventionin connection with specific apparatus, it is to be clearly understoodthat this description is made only by way of example and not as alimitation to the scope of the invention.

What is claimed is:

1. In a valve assembly, a first part formed of conductive metal andhaving a relatively thin-wall deformable portion forming the side wallof an open ended cavity, said side wall initially having a smooth,uninterrupted surface, and a second part having a portion extending intosaid cavity, said second part portion having means thereon facing saidwall for rigidly securing said first and second parts in assembledrelation, said wall being deformed into tight engagement with saidsecuring means by forces created by a transient magnetic field of highintensity, said first part comprising a valve body having a secondportion with a chamber therein communicating with said cavity, saidsecond body portion having at least one port therein communicating withsaid chamber, said second part comprising a valve top member with saidportion thereof having a bottom end closing said chamber, said topmember having a passage therethrough communicating with said chamberthrough said bottom end, said bottom end having a valve seat formedtherein, said top member having a port therein communicating with saidpassage, a valve member in said chamber, and a valve stem extendingthrough said passage and having said valve member secured thereto foractuating the same between a position engaging said seat therebyblocking flow between said ports, and a second position spaced from saidseat thereby permitting flow between said ports.

2. In a valve assembly, a first part formed of conductive metal andhaving a relatively thin-wall deformable portion forming the side wallof an open ended cavity, said side wall initially having a smooth,uninterrupted surface, and a second part having a portion extending intosaid cavity, said second part portion having means thereon facing saidwall for rigidly securing said first and second parts in assembledrelation, said wall being deformed into tight engagement with saidsecuring means by forces created by a transient magnetic field of highintensity, said first part comprising a valve body having a secondportion with a chamber therein communicating with said cavity, said bodyhaving an axis extending through said cavity and chamber, said secondbody portion having first and second axially displaced ports thereincommunicating with said chamber and a valve seat in said chamber betweensaid first and second ports, said second port comprising a valve topmember with said portion thereof having a bottom end closing saidchamber, said top member having a passage therethrough communicatingwith said chamber through said bottom end, and further comprising avalve member in said chamber, and a valve stem extending through saidpassage and having said valve member secured thereto for actuating thesame between a first position engaging said seat thereby blocking flowbetween said ports, and a second position spaced from said seat therebypermitting flow between said ports.

3. In a valve assembly, a first part formed of conductive metal andhaving a relatively thin-wall deformable portion forming the side wallof an open ended cavity, said side wall initially having a smooth,uninterrupted surface, and a second part having a portion extending intosaid cavity, said second part portion having means thereon facing saidwall for rigidly securing said first and second parts in assembledrelation, said wall being deformed into tight engagement with saidsecuring means by forces created by a transient magnetic field of highintensity, said valve being of the double seat type, said first partcomprising a valve body having a second portion with a chamber thereincommunicating with said cavity, said body having an axis extendingthrough said cavity and chamber, said second body portion having firstand second axially displaced ports therein communicating with saidchamber and a first valve seat in said chamber between said first andsecond ports, said second part comprising a valve top member with saidportion thereof having a bottom end closing said chamber, said topmember having a passage therethrough coaxial with said axis andcommunicating with said chamber, through said bottom end, said bottomend having a second valve seat formed therein, said top member having athird port therein communicating with said passage, and furthercomprising a valve member in said chamber between said first and secondseats, and a valve stem extending through said passage and having saidvalve member secured thereto for actuating the same between a firstposition engaging said first seat thereby blocking flow between saidfirst and second ports and permitting flow between said second and thirdports, and a second position engaging said second seat thereby blockingflow between said second and third ports and permitting flow betweensaid first and second ports.

4. The assembly of claim 3 wherein a portion of said valve stem axiallyspaced from said valve member has a threaded engagement with saidpassage thereby to actuate said valve member between said positionsthereof, said third port communicating with said passage between saidvalve stem portion and said bottom end of said top member when saidvalve member is in said second position thereof.

5. The assembly of claim 4 wherein said third port is a second passageformed in a nipple projecting from a side of said top member, saidsecond passage being inclined inwardly and downwardly toward saidfirstnamed passage and said bottom end of said top member.

6. The assembly of claim 3 wherein said holding means comprises acircumferential surface on said top member adjacent said bottom endwhich tapers axially inwardly in the direction away from said bottomend.

7. The assembly of claim 6 wherein said top member has a circumferentialgroove formed therein between said bottom end and said tapered surface,and further comprising an O-ring in said groove, said O-ring beingengaged by said deformed wall and compressed thereby.

8. The assembly of claim 6 wherein said holding means further comprisesaxially extending grooves formed in said tapered surface.

9. in a double seat valve assembly, a valve body having a firstthin-wall deformable portion forming the side wall of an open endedcavity and a second portion with a chamber therein communicating withsaid cavity, said side wall initially having a smooth, uninterruptedsurface, said body having an axis entending through said chamber andcavity, said second body portion having first and second axiallydisplaced ports therein commu nicating with said chamber and a firstvalve seat in said chamber between said first and second ports, a valvetop member having a portion extending into said cavity with a bottom endclosing said chamber, said top member portion having means thereonfacing said wall for rigidly securing said body and top member inassembled relation, said wall being deformed into tight engagement withsaid securing means, said top member having a passage therethroughcoaxial with said axis and communicating with said chamber through saidbottom end, said bottom end having a second valve seat formed therein,said top member having a third port therein communicating with saidpassage, a valve member in said chamber between said first and secondseats, and a valve stem extending through said passage and having saidvalve member secured thereto for actuating the same between a firstposition engaging said first seat thereby blocking flow between saidfirst and second ports and permitting flow between said second and thirdports, and a second position engaging said second seat thereby blockingflow between said second and third ports and permitting flow betweensaid first and second ports.

10. The assembly of claim 9 wherein said holding means comprises acircumferential surface on said top member adjacent said bottom endwhich tapers axially inwardly in the direction away from said bottomend.

11. The assembly of claim 10 wherein said top member has acircumferential groove formed therein between said bottom end andtapered surface, and further comprising an O-ring in said groove, saidO-ring being engaged by said deformed wall and compressed thereby.

12. The assembly of claim 10 wherein said holding means furthercomprises axially extending grooves formed in said tapered surface.

1. In a valve assembly, a first part formed of conductive metal andhaving a relatively thin-wall deformable portion forming the side wallof an Open ended cavity, said side wall initially having a smooth,uninterrupted surface, and a second part having a portion extending intosaid cavity, said second part portion having means thereon facing saidwall for rigidly securing said first and second parts in assembledrelation, said wall being deformed into tight engagement with saidsecuring means by forces created by a transient magnetic field of highintensity, said first part comprising a valve body having a secondportion with a chamber therein communicating with said cavity, saidsecond body portion having at least one port therein communicating withsaid chamber, said second part comprising a valve top member with saidportion thereof having a bottom end closing said chamber, said topmember having a passage therethrough communicating with said chamberthrough said bottom end, said bottom end having a valve seat formedtherein, said top member having a port therein communicating with saidpassage, a valve member in said chamber, and a valve stem extendingthrough said passage and having said valve member secured thereto foractuating the same between a position engaging said seat therebyblocking flow between said ports, and a second position spaced from saidseat thereby permitting flow between said ports.
 2. In a valve assembly,a first part formed of conductive metal and having a relativelythin-wall deformable portion forming the side wall of an open endedcavity, said side wall initially having a smooth, uninterrupted surface,and a second part having a portion extending into said cavity, saidsecond part portion having means thereon facing said wall for rigidlysecuring said first and second parts in assembled relation, said wallbeing deformed into tight engagement with said securing means by forcescreated by a transient magnetic field of high intensity, said first partcomprising a valve body having a second portion with a chamber thereincommunicating with said cavity, said body having an axis extendingthrough said cavity and chamber, said second body portion having firstand second axially displaced ports therein communicating with saidchamber and a valve seat in said chamber between said first and secondports, said second port comprising a valve top member with said portionthereof having a bottom end closing said chamber, said top member havinga passage therethrough communicating with said chamber through saidbottom end, and further comprising a valve member in said chamber, and avalve stem extending through said passage and having said valve membersecured thereto for actuating the same between a first position engagingsaid seat thereby blocking flow between said ports, and a secondposition spaced from said seat thereby permitting flow between saidports.
 3. In a valve assembly, a first part formed of conductive metaland having a relatively thin-wall deformable portion forming the sidewall of an open ended cavity, said side wall initially having a smooth,uninterrupted surface, and a second part having a portion extending intosaid cavity, said second part portion having means thereon facing saidwall for rigidly securing said first and second parts in assembledrelation, said wall being deformed into tight engagement with saidsecuring means by forces created by a transient magnetic field of highintensity, said valve being of the double seat type, said first partcomprising a valve body having a second portion with a chamber thereincommunicating with said cavity, said body having an axis extendingthrough said cavity and chamber, said second body portion having firstand second axially displaced ports therein communicating with saidchamber and a first valve seat in said chamber between said first andsecond ports, said second part comprising a valve top member with saidportion thereof having a bottom end closing said chamber, said topmember having a passage therethrough coaxial with said axis andcommunicating with said chamber, through said bottom end, said bottomend having a second valve seat formed therein, said top member having athird port therein communicating with said passage, and furthercomprising a valve member in said chamber between said first and secondseats, and a valve stem extending through said passage and having saidvalve member secured thereto for actuating the same between a firstposition engaging said first seat thereby blocking flow between saidfirst and second ports and permitting flow between said second and thirdports, and a second position engaging said second seat thereby blockingflow between said second and third ports and permitting flow betweensaid first and second ports.
 4. The assembly of claim 3 wherein aportion of said valve stem axially spaced from said valve member has athreaded engagement with said passage thereby to actuate said valvemember between said positions thereof, said third port communicatingwith said passage between said valve stem portion and said bottom end ofsaid top member when said valve member is in said second positionthereof.
 5. The assembly of claim 4 wherein said third port is a secondpassage formed in a nipple projecting from a side of said top member,said second passage being inclined inwardly and downwardly toward saidfirst-named passage and said bottom end of said top member.
 6. Theassembly of claim 3 wherein said holding means comprises acircumferential surface on said top member adjacent said bottom endwhich tapers axially inwardly in the direction away from said bottomend.
 7. The assembly of claim 6 wherein said top member has acircumferential groove formed therein between said bottom end and saidtapered surface, and further comprising an O-ring in said groove, saidO-ring being engaged by said deformed wall and compressed thereby. 8.The assembly of claim 6 wherein said holding means further comprisesaxially extending grooves formed in said tapered surface.
 9. In a doubleseat valve assembly, a valve body having a first thin-wall deformableportion forming the side wall of an open ended cavity and a secondportion with a chamber therein communicating with said cavity, said sidewall initially having a smooth, uninterrupted surface, said body havingan axis entending through said chamber and cavity, said second bodyportion having first and second axially displaced ports thereincommunicating with said chamber and a first valve seat in said chamberbetween said first and second ports, a valve top member having a portionextending into said cavity with a bottom end closing said chamber, saidtop member portion having means thereon facing said wall for rigidlysecuring said body and top member in assembled relation, said wall beingdeformed into tight engagement with said securing means, said top memberhaving a passage therethrough coaxial with said axis and communicatingwith said chamber through said bottom end, said bottom end having asecond valve seat formed therein, said top member having a third porttherein communicating with said passage, a valve member in said chamberbetween said first and second seats, and a valve stem extending throughsaid passage and having said valve member secured thereto for actuatingthe same between a first position engaging said first seat therebyblocking flow between said first and second ports and permitting flowbetween said second and third ports, and a second position engaging saidsecond seat thereby blocking flow between said second and third portsand permitting flow between said first and second ports.
 10. Theassembly of claim 9 wherein said holding means comprises acircumferential surface on said top member adjacent said bottom endwhich tapers axially inwardly in the direction away from said bottomend.
 11. The assembly of claim 10 wherein said top member has acircumferential groove formed therein between said bottom end andtapered surface, and further comprising an O-ring in said groove, saidO-ring being engaged by said deformed wall and compressed thereby. 12.The assemblY of claim 10 wherein said holding means further comprisesaxially extending grooves formed in said tapered surface.